1.1 本规范规定了公称直径为5 mm及以上的公制系列螺母和公称直径为英寸系列螺母的制造和加工过程中可能出现的各种类型的表面不连续性的允许限值 1. / 4. 英寸及更大。 1.2 以SI（公制）或英寸磅单位表示的数值应单独视为标准。每个系统中规定的数值并不完全相等；因此，每个系统必须独立使用。将两个系统的值组合在一起可能会导致不符合规范。 1.3 当应用的工程要求需要控制螺母的表面不连续性时，买方应在原始询价单和采购订单中说明是否符合本ASTM规范。 1.3.1 当应用的工程要求要求将螺母的表面不连续性控制在比本规范中规定的范围更近的范围内时，买方应在原始询价单和采购订单中规定适用的范围。 1.4 本规范中规定的标称直径为5至24mm（含）的公制螺母的允许极限与ISO/DIS中给出的要求基本相同 6157/II。对于公称直径大于24 mm的公制系列螺母或任何英制系列螺母的表面不连续性，没有ISO标准。 1.5 以下注意事项仅适用于试验方法部分，第节 7. ，本规范: 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。

1.1 This specification establishes allowable limits for the various types of surface discontinuities that may occur during the manufacture and processing of metric-series nuts with nominal diameters 5 mm and larger and inch-series nuts with nominal diameters 1 / 4 in. and larger. 1.2 The values stated in either SI (metric) or inch-pound units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 1.3 When the engineering requirements of the application necessitate control of surface discontinuities on nuts, the purchaser shall specify conformance to this ASTM specification in the original inquiry and purchase order. 1.3.1 When the engineering requirements of the application necessitate that surface discontinuities on nuts be controlled within limits closer than those specified in this specification, the purchaser shall specify the applicable limits in the original inquiry and purchase order. 1.4 The allowable limits established in this specification for metric nuts, with nominal diameters 5 to 24 mm inclusive, are essentially identical with requirements given in ISO/DIS 6157/II. There are no ISO standards for surface discontinuities on metric-series nuts with nominal diameters larger than 24 mm or on any inch-series nuts. 1.5 The following precautionary caveat pertains only to the test method portion, Section 7 , of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.